Background (Details) $ in Billions	9 Months Ended
	Sep. 30, 2015 USD ($) ft²
Nature of Business [Line Items]
Square Footage of Real Estate Property, Near-term and Future Development	11,600,000
Total Square Footage of Asset Base	31,471,007
Area of Real Estate Property	19,943,739
Total Market Capitalization | $	$ 10.8
Investment-grade client tenants as a percentage of total annualized base rent	53.00%
Percentage of leases which are triple net leases	96.00%
Percentage of leases containing effective annual rent escalations	95.00%
Percentage of leases providing for recapture of certain capital expenditures	94.00%
Minimum
Nature of Business [Line Items]
Effective annual rent escalations (as a percent)	3.00%
Maximum
Nature of Business [Line Items]
Effective annual rent escalations (as a percent)	3.50%